Pyruvate dehydrogenase phosphatase 1 deficiency / PDP1 deficiency (PDP1-related) - Dog

What does this test examine?

This genetic test analyses the PDP1 c.754C>T variant in the Clumber Spaniel and Sussex Spaniel. The condition is known as pyruvate dehydrogenase phosphatase 1 deficiency, PDP1 deficiency, pyruvate dehydrogenase deficiency and sometimes PDH complex deficiency. The result shows whether the dog carries zero, one or two copies of the tested variant.

PDP1 encodes an enzyme that helps activate the pyruvate dehydrogenase complex. This complex is essential for turning nutrients into usable cellular energy. When both gene copies carry the tested variant, this energy pathway is disrupted and the dog can develop problems during or after exercise.

What does this condition mean?

PDP1 deficiency is an inherited metabolic disorder. Affected dogs may only tolerate a short period of exercise, need to rest quickly and can collapse after exertion. Lactic acid accumulation, marked fatigue, muscle weakness, neurological signs and heart problems such as cardiomyopathy have also been described with this condition.

The condition is practically important because young dogs are not always immediately recognised as genetically affected. A DNA result clearly separates clear dogs, healthy carriers and dogs with two copies of the variant.

Inheritance and result

The trait is inherited in an autosomal recessive way. A clear dog does not carry the variant. A carrier has one copy and is usually not affected, but can pass the variant to offspring. A dog with two copies has the genotype that causes PDP1 deficiency.

• CC - no copy of the tested variant detected.
• CT - carrier: one copy of the tested variant detected.
• TT - affected genotype: two copies of the tested variant detected.

Practical value of this test

This test is valuable for breeders because carriers can look healthy. The result makes it possible to identify carriers, plan matings safely and avoid carrier-to-carrier combinations that can produce puppies with PDP1 deficiency.

For owners and breed clubs, the test provides clear information when exercise intolerance, unexplained fatigue or post-exercise collapse occurs in susceptible lines. In small populations such as the Clumber Spaniel and Sussex Spaniel, DNA testing helps balance health selection with preservation of genetic diversity.